How long to melt plastic through composite material?

  • Thread starter Thread starter David McKnight
  • Start date Start date
  • Tags Tags
    Heat Heat transfer
AI Thread Summary
To calculate the time required to melt polyethylene plastic through a composite material, one must consider the thermal properties of both the paper and aluminum layers. The equations involved include the heat transfer equation dQ/dt = kTA dT/dx, where k represents thermal conductivity, A is the area, and dT/dx is the temperature gradient. The composite's effective thermal conductivity can be determined using the equation 1/kT = 1/kPaper + 1/kAlu. The power supplied to the system is 1500 W, and the temperature gradient is derived from the difference between the heat source (350 F) and the melting point of the plastic (325 F). Additionally, the heat capacity of the plastic should be factored into the calculations to accurately determine the melting time.
David McKnight
Messages
2
Reaction score
0
How could I calculate how much time would be required to melt a plastic through a composite material?

Composite is .005 inches paper and .0003 inches of Aluminum
Plastic is .001 inches polyethlene with melting point of 325 F

Assume heat source is uniform across area of composite
 
Physics news on Phys.org
According to the Physics Forums Guidelines (which you agreed to), you have to show how you started this problem.
 
What I've done so far is research and realized my ability of working with differential calculus is lacking. But I do believe that the equations needed are:

dQ/dt = kTA dT/dx

1/kT=1/kPaper +1/ kAlu (so I can figure this out)

A = 2pi 4 inches (1/8 inches)

dQ/dt = the power supplied to the paper side which 1500 W – but I need to solve for dt (not sure how to re-arrange diff calc formula)

dT/dx = (350-73) F to 25 F (So heat source is set at 350 F and the melt point of plastic is 325 F)

I believe I need to consider the heat capacity of the plastic but I’m not sure where – should it be added to the (kT) formula?
 
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Thread 'Correct statement about a reservoir with an outlet pipe'
The answer to this question is statements (ii) and (iv) are correct. (i) This is FALSE because the speed of water in the tap is greater than speed at the water surface (ii) I don't even understand this statement. What does the "seal" part have to do with water flowing out? Won't the water still flow out through the tap until the tank is empty whether the reservoir is sealed or not? (iii) In my opinion, this statement would be correct. Increasing the gravitational potential energy of the...
Back
Top